Get out some of your fabric. If she knows or is learning her colors you can have her point to the colors and tell you what they are. Or if any of your fabric has animals on it do the same thing in naming the animals.
Also read to her, even if you have to find a children's story book on line if you don't have one.
Play peek a boo. Play with her toys with her.
If she is up past her bed time she may just fall asleep in the car. If not, she may be cranky. Have her favorite blankee or toy at hand.
Sing to her.
Hold her and cuddle with her and cherish the time together!
Have fun. And drive carefully.